anti- convulsants Flashcards
1
Q
What are neurotransmitter receptors?
A
proteins
2
Q
What do neurotransmitter receptors match?
A
match the size & shape of a neurotransmitter
3
Q
How are neurotransmitter receptors named?
A
named according to the transmitter they bind with
4
Q
neurotransmitters are ______________ or ______________ depending on the type of receptor it bind to
A
inhibitory or excitatory
5
Q
What neurotransmitters are inhibitory?
A
- dopamine
- serotonin
- GABA
6
Q
What neurotransmitters are excitatory?
A
- acetylcholine (ACH)
- norepinephrine
7
Q
Where is acetylcholine (ACH) found?
A
found in CNS, PNS, & ANS
8
Q
is ACH excitatory or inhibitory?
A
can be either excitatory or inhibitory depending on the neurons secreting it
9
Q
Is ACH excitatory or inhibitory in the parasympathetic nervous system?
A
excitatory at neuromuscular junction
10
Q
is ACH excitatory or inhibitory in the autonomic nervous system?
A
inhibitory; slows HR
11
Q
What is serotonin (5-hydroxytryptamine) derived from?
A
derived from tryptophan
12
Q
Where is serotonin primarily found?
A
- GI tract
- platelets
- brainstem
13
Q
What feeling does serotonin contribute to?
A
contributes to feeling of well being & mood regulation
14
Q
Where is dopamine mainly located?
A
in the substantia nigra of midbrain/basal ganglia region
15
Q
What does dopamine control?
A
- behavior & cognition
- volutary motor movement
- motivation & punishment
- reward & attention
- memory
- learning
16
Q
What neuropsychiatric & voluntary motor movement disorders is dopamine involved in?
A
- social phobia
- ADHD
- SUD
- parkininsons
- tourettes
17
Q
What is the chief inhibitory transmitter in the CNS?
A
gamma amino butyric acid (GABA)
18
Q
What effect does GABA have on the brain?
A
relaxing, antianxiety & aniconvulsant effect on brain
19
Q
What effect does GABA have on the muscles?
A
inhibitory effect on muscles (decrease muscle spasm & improve tone)
20
Q
What is norepinephrine in the brain?
A
an excitatory neurotransmitter in the brain
21
Q
What is norepinephrine in the endocrine system?
A
a stress hormone within the endocrine system
22
Q
What part of the nervous system is norepinephrine a part of?
A
sympathetic nervous system
23
Q
what does norepinephrine play a role in?
A
plays a role in fight or flight response
24
Q
What is glutamate a major mediator of?
A
major mediator of excitatory signal
25
What functions is glutamate involved in?
- cognition
- memory
- learning
26
What is action potential (neuron conduct impulses)?
- abrupt changes in membrane potential which permit nerve signals to be transmitted from the cell body down the axon
- stimulated sodium, potassium, & calcium ions to move across axon membrane
27
In what state are neurons usually?
polarized (negatively charged state)
28
What happens when a neuron receives a signal?
it becomes positively charged & this increase in positive charge sens the message down the nerve
29
What are the three phases of action potential?
- depolarization of the neuron = positively charged ion
- repolarization of neuron = return of neuron to a negative value
- resting period
30
What impulses can lead to seizures?
impulses that do not maintain a systematic order (excitatory, inhibitory, & rest phase become irregular & chaotic) can lead to seizures
31
What is a seizure?
a single episode of abnormal electrical discharge from cortical neurons that results in an abrupt & temporary altered state
32
What is epilepsy?
a group od syndromes characterized by unprovoked, recurrent seizures
33
What is status epillepticus?
continuous seizure activity for more than 5 minutes or 2 or more sequential seizures that occur without full recovery of consciousness between attacks
34
What are the common causes of seizures?
trauma
ETOH withdrawal
illicit drug use
brain tumor
congenital malformations
stroke
metabolic disorders
- uremia, electrolyte imbalance
alzheimers
neurodegenerative disease
idiopathic
35
What can trigger a seizure?
- flashing lights
- stress
- certain drugs
- metabolic changes
36
What are the 5 common causes of epilepsy?
genetic causes
head trauma
medical disorders
prenatal injury
developmental disorders
37
What should we know about genetic causes of epilepsy
> 30 mutated genes have been found in families with epilepsy
- may occur in genes coding for different things (ex. ion channels, neuronal receptors, transcription factors)
- many pediatric epilepsies are associated w/ randon gene mutation for the first time (de novo)
- about half of seizure disorders, no genetic or structural abnormality is present
38
What medical disorders can cause epilepsy?
- dementia
- meningitis
- encephalitis
39
What developmental disorders can cause epilepsy?
- autism
- down syndrome
40
how do seizures work?
- messages from the body are carried by the neurons (nerve cells) of the brain through discharges of electrochemical energy
- these impulses occur in bursts
- during periods of unwanted discharges, parts of the body may act erratically
41
What is needed for an actual seizure to occur?
- excitable neurons
- increased excitatory glutaminergic activity
- reduction in activity of normal inhibitory GABa projection
42
Who can have a seizure?
anyone!
43
what are the two classifications of seizures?
focal or partial
generalized
44
what are the two kinds of focal or partial seizures?
simple partial
complex partial
45
What are the types of generalized seizures?
absence (petit mal)
tonic-clonic (grand mal)
atonic/akinetic (drop attacks)
status epilepticus
46
Where in the brain are focal seizures?
start 7 remain in 1 hemisphere
47
In focal seizures there are _____- ___________ burst of action potentials 7 ____________________
high- frequency; hypersynchronization (large number of neurons dire action potentials together)
48
what do focal seizure affect?
sensory & motor function
autonomic sx
automatism
49
What are the autonomic sx of focal seizures?
due to stimulation of ANS
- pallor
- sweating
- pupillary dilation
- epigastric sensation
50
What is automatism?
coordinated involuntary movements occuring during state of impaired consciousness either during or after seizure. Pt is unaware, often associated with temporal seizures
51
Is pt aware or unaware in focal seizures?
awareness can be maintained or lost
52
do pts have aura with focal seizures?
some may experience a warming sensation before seizure
53
What are characteristics of focal seizures when pt retains awareness?
- no impairment of consciousness
- similar to partial seizures
- may have movement of body parts
- may experience an aura
54
What are characteristics of a focal seizure when awareness is altered?
- impairment of consciousness
- spreads to both hemispheres
55
What are characteristics of partial seizures?
- begins in part of one hemisphere (typically in the temporal lobe)
- may be simple or complex
56
In what part of the brain does a generalized seizure occur?
- start in 1 hemisphere & spreads w/ involvement of both hemisphere
- affects both hemispheres of the brain
57
do generalized seizures have motor sx?
may have motor and/or nonmotor sx
58
is consciousness maintained or impaired in generalized seizures?
impairment of consciousness
59
What occurs in a tonic-clonic seizure (grand mal)?
begin with rigid violent contractions (tonic) followed by repetitive clonic activity of all extremities; body stiffness & relaxation
60
What are tonic seizures characterized by?
- muscle stiffness
- dilation of pupils
- altered respirations
- usually less than a minute
61
what are absence seizures characterized by?
short episodes of staring & loss of consciousness
- last around 10 seconds
62
What are myoclonic seizures characterized by?
- bilateral jerking of muscles
- no loss of consciousness
63
What are atonic seizures characterized by?
- sudden loss of muscle tone causing a person to collapse or drop to the ground
64
is status epilepticus an emergency?
yes; a neurological emergency
65
What does status epilepticus need?
requires immediate intervention because of the extreme energy expenditure & potential lack of oxygen during prolonged seizures
66
how is a seizure dx?
H & P
neurological exam
diagnostic procedures
67
What diagnostic procedures are used to dx a seizure?
- chemistries/ blood work for toxins to check for drug-related causes
- toxicology screen
- CT/MRI to r/o structural causes like tumors
- EEG to measure brain rhythms & to capture abnormal brain activity during a seizure
68
What are the three phase of a seizure?
pre-ictal
ictal
post-ictal
69
What is the pre-ictal phase of a seizure?
when seizure may be started by a trigger and/or preceded by an aura
70
What happens during the ictal phase of a seizure?
- actual seizure
- increases in metabolic demand
71
What happens in the post-ictal phase?
- has decreased responsiveness
- feels fatigue
72
What is important to do during the post-ictal phase?
keep pt safe & monitor their recovery
73
What are anticonvulsants also known as?
antiepileptic drugs (AED)
74
What are indications for anticonvulsants?
- used for long term management of chronic epilespsy
- management of seizures not caused by epilepsy
- off-label uses
75
What are the off-label uses for anticonvulsants?
- anxiety
- bipolar disorder
- chronic pain
- migraines
76
What is selection of medication for tx based on?
classification of seizures & epilepsy
- broad spectrum
- narrow-spectrum
77
What are broad spectrum anticonvulsants used for?
effective for tx of focal & generalized seizure
78
What are narrow spectrum anticonvulsants used for?
used primarily for focal- onset seizures (including focal which evolve to b/l convulsive seizures)
79
What are the factors that are evaluated when selecting an anticonvulsant medication?
- efficacy
- tolerability
- presence of comorbidites
- pharmacokinetic profile
- potential drug-drug interactions
- ease of use
- cost
-age
- gender
80
list examples of anticonvulsants that work as NA+ channel blockers?
- carbamazepine
- oxcarbazepine (trileptal)
- eslicarbazepine
- felbamate
- lamotrigine
- lacosamide ( vimpat)
- phenytoin & fosphenytoin(IV)
- topiramate
- valproate
- rufinamide
81
list examples of anticonvusants that work as glutamate receptor blockers?
- topiramate
- zonisamide (zonegran)
- perampanel
- felbate
- levetiracetam
- brivaracetam (PO, IV only > 16 yo)
82
list examples of anticonvusants that work as calcium channel blockers?
- ethosuximide
- gabapentin
- lamotrigine (lamictal)
- pregabalin
- valproic acid
- zonisamide
83
list examples of anticonvusants that work as GABA enhancers?
- benzodiazepines
- barbiturates
- valproic acid (depakote)
- gabapentin
- pregabalin
- ethosuximide
84
How do meds that block sodium channels work?
- prevent return of the channel to active state; stabilizes them; inactive state
- prevent repetitive firing
85
How do meds that block calcium channels work?
- calcium going in during cells resting state facilities development of an action potential
- inhibits slow depolarization which is needed for spike-wave bursts
- these meds help to "lock the channel"
86
How do meds that enhance GABA work?
- may enhance Cl- influx which makes cell more negative and harder for cell to generate action potential
- some decrease metabolism of GABA so more is available
87
How do meds that block glutamate work?
- bind glutamate which is an excitatory neurotransmitter
- glutamate receptor has 5 potential binding sites
88
anticonvulsants are to __________ seizures; not ____
control; cure
89
What is the anticonvulsant prescribed based on?
type of seizure
90
What do many anticonvulsants require?
blood monitoring
91
What patient education should be given related to anticonvulsants?
- take as precribed
- never stop taking on own
- side effect management
92
What class is phenytoin a part of?
sodium channel blocker
93
How does phenytoin work?
- works to stabilize the neurons from becoming too excited
- stops the spread of seizure activity in the motor cortex
94
phenytoin is _______ (90%) protein- bound meaning it has a higher risk for ______ _____________
highly; drug interactions
95
What are indications for Phenytoin?
tonic- clonic seizures
status epilepticus
prophylaxis for surgery
96
What is the therapeutic range for phenytoin?
10-20mcg/ml; very narrow therapeutic range
97
What should you monitor in pts taking phenytoin?
peak & troughs
98
What are the routes of administration for phenytoin?
PO, IM, & IV
99
What are precautions for giving IV phenytoin?
- infuse over 30-60 minutes
- can be very irritating to veins
100
What should you do for those taking phenytoin & on tube feeds?
need to stop tube feed for 2 hrs before & after giving med
101
What are the side effects of phenytoin?
neurologic
- drowsiness
- ataxia
- irritability
- visual problems
- peripheral neuropathy
- N/V
- headache
cardiovascular
- hypotension
- arrhythmias
skin
- rash
- steven- johnsons syndrome
other
- suicidal thoughts
- gingival hyperplasia (gum overgrowth)
102
How does phenobarbital work?
inactivates fast sodium channels leading to enhanced GABA effects & decreased glutamate release
103
What class is phenobarbital in?
barbiturates
104
What is the half-life of phenobarbital?
very long half-life
105
What are the side effects of phenobarbital?
- sedation
- respiratory depression
- diplopia (double vision)
- cognitive skill impairment
- hypotension
- hyperactivity & inattention in children
106
What can phenobarbital cause?
physical dependence
107
What is carbamazepine's mechanism of action similar to?
phenytoin
108
What class does carbamazepine belong to?
sodium channel blockers
109
What types of seizures is carbamazepine used for?
- used for several different types of seizures
- drig of choice for partial & generalized tonic-clonic seizures
- avoid in absence or myoclonic seizures as it may worsen them
110
Carbamazepine inhibits the spread of __________ activity
seizures
111
Where should carbamazepine be kept?
needs to be kept in a dry location (not a bathroom)
112
for what disorders is carbamazepine used off-label?
- trigeminal neuralgia
- bipolar disorder
113
What does carbamazepine interact with?
oral contraceptives; reducing their effectiveness
114
What labs should be performed when taking carbamazepine?
CBC (esp. WBC)
drug levels
sodium
CBC
LFTs
BUN/Cr (esp in those with renal impairment)
115
What is the therapuetic level of carbamazepine?
4-12 mcg/ml
116
What are side effects of carbamazepine?
- rash
- steven johnson syndrome
- increased SI
- headache
- diplopia
- ataxia
- drowsiness
- sedation
- N/V
- hyponatremia
- decreased blood counts (neutropenia & thrombocytopenia)
117
should carbamazepine be taken with or without food?
take with food
118
What should you never do when taking carbamazepine?
stop abruptly
119
oxycarbazepine has the same efficacy as _________________, but is better tolerated
carbamazepine
120
What does oxycarbazepine work as?
a sodium channel blocker
121
When is oxycarazepine used?
used as adjunctive therapy or monotherapy for partial seizures in children & adults
122
With what seizures should oxycarbazepine not be used?
absence & myoclonic because it may worsen them
123
oxycarbazepine decreases efficacy of _____ _______________
oral contraceptives
124
What can oxycarbazepine increase the risk of?
suicidal ideations
125
How does valproic acid/ valproate work?
inactivation of fast sodium channels; GABA enhancer
126
What are the indications for valproic acid?
- absence seizures
- myoclonic seizures
- tonic-clonic seizures
- partial seizures
- neonatal seizures
127
When is valproic acid used off-label?
used to contol sx of acute mania in bipolar disorder
128
What can valproic acid be given with?
phenytoin
129
What are the side effects of valproic acid?
- N/V
- sedation/ dizziness
- pancreatitis
- increased ammonia levels
- thrombocytopenia (monitor CBC)
- suicidal thoughts
- liver toxicity
130
What should you monitor with a pt on valproic acid?
monitor CBC
monitor LFTs
check therapeutic levels
131
What is the therapeutic level of valproic acid?
50-100 mcg/ml; narrow therapeutic range
132
Should valproic acid be taken with or without food?
taken with food
133
How should IV valproic acid be given?
- must be diluted with at least 50ml NSS or D5W
- give over an hour (no more than 20mg/min)
134
What should you avoid with valproic acid?
avoid sudden withdrawal
135
How does gabapentin work?
thought to act on calcium channels to decrease glutamate & increase GABA in the brain
136
What are indications for gabapentin?
partial seizures
new onset epilepsy
137
with what seizures should gabapentin not be given?
myoclonic seizures; may worsen them
138
What are the off- label uses for gabapentin?
- chronic neuropathic pain
- anxiety
- hot flashes/night sweats
- headaches
- hiccups
- alcohol withdrawal
139
What are the side effects of gabapentin?
- fatigue (often given at night)
- mental cloudiness
- leukopenia
- edema
- weight gain
- emotional lability
- tremors
- GI side effects
- suicidal thoughts
140
What should you do for renal patients taking gabapentin?
reduce dose in renal patients
141
when should gabapentin be used cautiously?
cautious use in those with an addiction history
142
Do you need to monitor drug levels for gabapentin?
no
143
how should you stop gabapentin?
withdrawal slowly
144
When will gabapentin doses be very high?
doses will be very high for pain control
